Inclosed fuse.



B.' TRESCOTT.

lNcLosgD FUSE.

APPLiCATION FILED JAN. 2, 1917.

G.MCD.10HNS 5.1.

Patented Mar. 11, 1919.

es" v im UNITED sTATEs PATENT oEEroE.

GEORGE MCD. J'OI-IIIIS, OF ST. LOUIS, AND JOHN B. TRESCOTT, OF MIDLAND HEIGHTS, MISSOURI, ASSIGNORS T0 KILLARK ELECTRIC MANUFACTURING COMPANY, 0F ST. LOUIS, MISSOURI, A CORPORATION 0F MISSOURI.

INCLOSED FUSE.

Specification of Letters Patent. Patented Mar. 119 1919.

Application led January 2, 1917. Serial No. 140,120.

To all whom t may concern.'

Be it known that we, GEORGE MCD. JOHNS. and JOHN B. TREsCoTT, citizens of the United States, residing respectively at the city of St. Louis, State of Missouri, and at Midland Heights, St. Louis county, Missouri, have jointly invented certain new and useful Improvements in Inclosed Fuses, of which the following is a specification, reference being had to the accompanying drawing, forming a part thereof.

This invention relates generally to electric safety fuses and, more particularly, to certain new and useful improvements in that class of electric safety fuses commonly known as renewable inclosed or cartridge fuses.

The chief objects of our present invention are to provide an electric safety fuse 1n which the fusible-element or strip may be readily and conveniently renewed when blown or disrupted by an excess of current, the more expensive casing or shell and terminals or other ttings of the fuse being retained and repeatedly used; to provide a fuse of the class mentioned vin which,l on the blowing of the original fusible element or strip, it is most difficult, if not impossible, to employ or substitute a fusible-element or strip of different or greater carrying-capacity than the rated capacity of the original fuse; to provide a renewable fuse with inexpensive means adapted to indicate the blowing or disruption of the fusible-element or strip; to provide an efficient fuse of the class stated of simple and economical construction, of few readily assembled and renewable parts or members, parts or members are securely held in operative relation by frictional engagement therebetween; and to improve generally upon and simplify the construction of fuses of the class described. i

With the above and other objects in yiew, ourv present invention resides in certain novel features of form, construction, arrangement, and combination of parts, all as will hereinafter be described and afterward pointed out in the claims.

In the accompanying drawing- Figure 1 is a longitudinal sectional view of' an inclosed fuse of the knife-blade type embodying our-invention;

Fig-2 is an end view of the same;

and in which the.

Fig. 3 is a longitudinal sectional view through the fuse taken approximately at right angles to the sectional view of Fig. 1.

Fig. 4 is a transverse sectional view through the fuse on approximately the line 4r4, Fig. 1;

Fig. 5 is an enlarged plan view of the renewable fusible-element or Istrip f ormingl part of the fuse; Figs. 6 and 7 are opposite end views of the fusible-element or strip;

Fig. 8 is a side edge view of the fusibleelement or strip;

Fig. 9 is an elevational view, partly in longitudinal section; of an inclosed fuse of the ferrule type embodying our invention;

Fig. 10 is a similar view taken approximately at right angles to the view of Fig. 9;

Fig. 11 is a plan view of one of the pairs of strip-engaging and securing members or jaws of the fuse Figs. 12 and 13 are opposite end views of the same;

Fig. 14 is a side edge view thereof; and

Fig. 15 is a transverse section through a fuse of our construction, embodying a modilied form of said securing-members or jaws. Referring to the said drawing, in which like reference characters refer to like parts throughout the several views, 1 indicates the fuse-casing, which is referably an openended tubular shell of brous or other suitable insulation material, and which may be of any suitable length and diameter as required according to the desired size or current-carrying capacity of the fuse. At each end, he casing or shell 1 is cut away inwardly, the casing or shell being thereby provided longitudinally with alining pairs of diametrically opposite slots 2-2; and since the construction of the fuse at each end of the casing or shell 1 is substantially identical, the construction` of 4the fuse at one end of the casing only will be here in detail described.

3 indicates a sleeve or annulus of thin steel or other suitable metallic material,

which is iitted about the end of shell 1 and transversely or crosswise i of shell 1 with its ends disposedin the slots 2V and welded or otherwise fixed to the sleeve 3,

` shortly to appear,y

is a bar 5. This bar 5, which at its ends is approximately rectangular in shape in cross section, is intermediate its ends, for purposes suitably bent longitudinally thereof into whatmight be described as an odd, crooked, sinuous, or peculiar shape, as, for instance, into the approximately S-shape seen particularly in Fig. 4.

7 indicates the renewable element or fusible-strip of the fuse, which may be of any suitable readily fusible metal or alloy, and which is of the desired ampere carryingcapacity, as will be well understood. This strip 7 is also of approximatel with the length of the shell 1, the strip 7 `iieing adapted to extend longitudinally of and within the shell, as seen particularly in Figs. 1 and 3, to one side .of both the fixed bars 5. At one endof strip 7 is a preferably integral extension 8, which isv bent, as at 9, over upon the strip 7 'to form or provide a hook-for engagement withone of the fixed bars 5 in the assembling of the fuse. At the other end of strip 7 is also a preferably integralv extension 10 having a length approximately equal to or less than the internal radius of the shell 1, so that the extension 10, in the assembling of the fuse, may be conveniently and easily folded within the shell over upon, and the strip 7 there- /by engaged with, the other or opposite fixed y partly dat throughout bar 5. The strip 7 is its length and area; but to eiciently engage electrically with, and conform preferably to a portion of on'e side or face of, thebars 5, the strip 7 is pressed or otherwise formed longitudinally at its ends and approximately on opposite sides of its longitudinal axis 4with elongated' concavities orV rounded de-V pressions ll-ellof a curvature corresponding with, and toy neatlyfit, a portion ofthe under face ofthe bars 5, as illustrated in Fig. 4. Similarly, extension 8, while partly fiat, is suitably formed longitudinally with a convexed or rounded portion, as at 12, to conform partly to the other or upper face of one of the bars 5, the convexed portion 12 of extension 8 and depression 11 of strip 7, while partly overlapping at their inner edges, extending for the mostpart upon opposite sides of the longitudinal axis of the strip. Likewlse, 'extension 10, while also partly fiat, is preferably formed or provided for the 'same purposefin lconnection -with the opposite bar 5 with a correspondingly convexed or rounded portion, as at 13. Thus the strip 7,. when operatively positioned within the shell 1, is adapted tosmoothly Aand neatly fit upon and engage with'both sides or faces of the fixed bars 5.

. 14 indicates a suitable flanged or cupshaped metallic cap, which is adapted, in the finished or assembled f se, to snugl yfit removably or detachably upon, and ally engage with, the sleeve 3 and provide a a length corresponding rictionneeaeos closure for the end of the shell 1. The cap 14 is provided in its end wall with perforations, as at 15, constituting vents for the escape of gas from the interior evolved on the blowing of a strip 7, a screening-diskvl disposed flatwise upon the inner face of the end wall of the cap 14 preventing the escape through the vent-perforations l5 of molten or other particles of a blown or disrupted strip. The end-cap, as well as also the screening-disk vin the knife-blade type of our fuse, as illustrated in Figs. 1 and 3, are provided with an elongated approximately rectangular slot, projecting outwardly through which vlongitudinally of the shell l is a knife-blade terminal 17 formed `preferably by doubling or bending an elongated section of metal, preferably hard rolled copper, upon itself.

The said copper or other suitable metallic,

their inner edges, lying or extending for the most part upon opposite sides of the longitudinal axis the other and which are inherently somewhat resilient or spring-like, are adapted, when the end-cap is fitted upon the shell, to clampingly engage with. the bar 5 and the fusible stripeither hooked orfolded there-- upon to securely hold the sametogether with'= the strip and jaws and their end-cap in ap-l proximately trical contact.

sleeves 3 with theirbars 5 are fixed upon the ends of the shell 1, as

end-cap 14.- With its jaws 18. is then fitted upon the shell and its jaws 18. forced or projected intoclamping engagement with the= bar 5 and/said hooked end of the strip 7..

The opposite end of the strip 7 is then at its extension 10 bent or folded into engagement with the opposite or other bar 5, when theother end-cap 14 is similarly fitted upon the shell. 0n the blowing or disruption of the-i strip 7 on an excessof current, the end-caps 14, by a positive endwise pull thereupon,

of the cap, as: each pressed orA to conform to portion 19 and al longitudinally-- disposed rounded portion 20, the roundedv portions 20 of the jaws- 18 being oppositel'yl disposed and, while slightly overlapping at of the jaws. Thus the j'a-ws 18,1, which are suitably spaced apart one from:

or substantially perfect elec-- may be: readily removed or detached from the shell, a new strip 7 substituted, andthe parts again assembled as described, the shell, end-caps, and other and more expensive parts or fittings of the fuse being retained and repeatedly used; and it will now be evident that, due to the peculiar or. odd conformation or shape of the bars 5 and jaws 18, a new strip possessing the characteristics and rated capacity of the original or blown fuse-strip may onl be substituted therefor. Under the frlctional engagement between the caps 14 and sleeves 3, and the fuse in practice being held in suitable clips, the caps 14 are securely held from being accidentally blown off the shell on the disruption of the fusible-element or strip on an excess of current, thus in our fuse rendering the use of rivets, screws, or other holding-means for the caps unnecessary; but it will be obvious that additional means for removably or detachably holding the caps upon the shell may be provided, if desired.

The ferrule type of our fuse illustrated particularly in Figs. 9 to 14both inclusive, is substantially similar in construction and operation to the knife-blade type of our fuse before described, and a detail descrip-tion of the same here would, therefore, be more repetition and is hence omitted. In this type of our fuse, however, in which the end-caps or ferrules form the terminals of the fuse, a suitable section of copper or other conducting material is merely bent to an approximately U-shape in side elevation to provide the strip-engaging or clamping jaws 18', which are welded or otherwise fixed at their bight, as at 21, to the inner face of the end wall of the cap 14.-', slots in the end-capsv 14 to accomodate knife-blade terminals be ing omitted.

And preferably both types of our fuse are equipped or provided with comparachemical-mixture, we preferably employ a mixture 24 including lodid of copper and iodide of mercury in approximately equal parts, together with gum larabic of other suitable binder. This mixture normally is of a red color, but under the influence f heat evolved on the blowing of a'fusiblestrip 7 and at approximately 140 F., turnsA black in color, the mixture on cooling again assuming its normal red color. Thus the blowing or disruption of a fusible-strip 7 is substantially at once visually indicated'. Disposed in the cup 23 over the mixture 24 or the like to a user in removing a fuse froman uninterrupted or closed circuit.

From the foregoing, it will be evident that our fuse 1s comparatlvely simple in construction, may be economically and cheaply.

manufactured, and comprises readily assembled and renewable parts. And it is to be understood that the fusible-strip 7 at its ends, as .well as the jaws 18 or 18', may have,

if desired, the modified or substantially full S-shape-form in cross section, as illustratedv in Fig. 15, to correspond or conform fully to the shape of the bars 5, and that other changes in the form, construction, arrangement, and combination of the several parts of our fuse may be made and substituted for those herein shown and described without departing from the nature and principle of our invention. f

4 Having thus described our invention, what we claim and desire to secure by Letters Patent is: V

1. A renewable fuse of the class described comprising, in combination, a shell, a bar extending transversely across the shell at an end, the bar being fixed at its ends to the shell, a fuse-strip extending longitudinally within the shell, the strip having an end removably disposed upon said bar, an endcap fitting removably upon the shell, and cooperating jaws on the end-cap projecting into the shell, said jaws clampingly engaging removably with the strip and-bar for detachablysecuring the same together.

2. A renewable fuse ofthe class describen comprising, in combination, a shell, a bar extending transversely across the shell at an end, the -bar being fixed at its ends to the shell, a fuse-stri extending longitudinally within the she l, the strip having an end bentfto lie upon opposite sides of and l infold the bar, an end-cap tting removably upon the shell, and a pair of coperating'jaws on the cap projecting into the shell, said jaws clampingly engaging the bent end of the strip and the infolded bar for detachably securing the strip and bar together.

3. A renewable fuse of the class described comprising, in' combination, a shell having diametricarlly opposite slots at its end, a

,sleeve fixed upon the said end ofthe shell and concealing said slots, a bar extending transversely across the shell at its said end, the bar having its ends" projecting through said slots and fixed to the sleeve, a fusestrip extending longitudinally within the the cap strip and the infolded bar for Vdetachably securing the strip and bar together.

4. In a renewable fuse,lthe combination with a shell, of a bar extendin transversely across, and yhavin its ends xe to, the shell, said bar interme iate its ends being sinuous in shape in'longitudinal section, and a fusestrip adapted for insertion within the shell and to engage at an end with said bar, the strip having a. shape at its said end to conform approximately to the shape of the bar.

5` In a renewable fuse, the combination with a' shell, of a bar extendin transversely across, and having its ends x to', the shell, the bar vintermediate its ends being sinuous in shape in longitudinal section, and a fusestrip adapted for insertion within the shell and at an end to extend upon opposite sides of and infold said bar, the strip\having a shape at its said end to conform approxinately with the opposite side faces of the i ar.

6. In a renewable fuse, the combination with a shell, of .a bar extendin transversely across, and having its ends ixe to, the shell, the bar intermedlate its ends bein sinuous in shape in longitudinal section, a' use-strip adapted for insertion within the shell and at an -end to extend upon opposite sides of and infold said bar, the strip having a shape .at its said end to conform approximately with the opposite side faces of the bar, an 'end cap adapted to t removably upon the shell, and a pair of coperating jaws on the end-ca adapted to clampingly engage said end o the strip and the infolded bar to lsecure the strip and bar detachably together, fsald jaws having a shape in cross section to conform approximately with the opposite slde faces of the bar.

7. In a renewable fuse, an open-end shell, a sleeve fixed on an end of the shell, a fusestr1p supporting-bar-extending transversely across the shell and fixed at its ends to said sleeve, said bar being sinusoidal in shape in longitudinal section, a fuse-strip disposed longitudinally within the shell and supported at an end on saidbar, said strip having a` shape in 'cross section at its end conforming approximately yto the shape of said bar,

a cap removablyfltting upon the sleeve and providing v a closure for the end of the shell,

f and a air of cooperating jaws on the cap reovab y' engaging with the stri and bar gdr detachably securing the same eplectrically i posed depression.

aaeaeee together, said jaws having also a shape in cross section confgrming approximately to the shape of said bar. l

8. In a fuse, a flat fuse-strip provided within4 its area with a longitudinally dis- 9. In a fuse, a flat fuse-strip provided at each of its ends and within its area with a longitudinally disposed rounded depression, said 'depresslons lyin for the most part upon opposite sides o the longitudinal axis of the strip.

10. In a fuse, a fuse-strip adapted at its end to engage the opposite faces of a sinuous supporting-bar, the strip comprising an end-portion sinuous in shape to 'conform approximately with one face of the bar, and a foldable extension sinuous in shape to conform approximately with the opposite face of the bar. j.,

11. In a fuse, a fusestrip provided longitudinally with elongated roundedl depressions, and extensions on the fuse stri provided also with rounded depressions, t e depressions of said extensions opposing the depressions of the strip.

12; In a fuse of the class described, a shell, a fuse-strip, within the shell, an endcap fitting upon the shell and having engagement with the strip, and an insulationcap fitting upon the shell over said end-cap.

13. In a fuse of the class described, the combination with a shell, of b-ars extending transversely across the shell at its end, said bars having their ends fixed to the shell, a fuse-strip fitting within the shell and engaging at its ends with the corresponding faces of both said bars, said strip having extensions at its ends infolding, and engaging the opposite faces of, said bars, and end-caps fitting upon the shell and having electrical connection with the strip. i

14. In a fuse of the class described, the combination with a shell, sleeves xed upon the shell at its ends, bars extending transversely across the shell at its ends, said bars having their ends projecting through the shell and fixed to said sleeves, a fuse-strip fitting withinthe shell a-nd engaging at its ends with thecorresponding faces of both infolding, and engaging the opposite faces said bars, foldable extensions on said strip of, said bars, and caps tting upon [the I sleeves and providing closures for the ends of the shell, the .caps having electrical connection with the strip.

In testimony whereof., we have signed our names to this specifcatlon.

GEORGE MCD. JOHNS: .roHN n. 'ranscorr 

